Spain day-ahead electricity price and wind power forecast

Forecasting the Spanish electricity price

Spain is a single bidding zone covering the peninsula, so one day-ahead price applies across all of it. OpenWindCast forecasts all 24 hours of tomorrow's delivery day, using only information available before the auction closes.

The Spanish day-ahead auction sets one price per hour for the whole peninsular bidding zone, and it closes at 12:00 CET for the following delivery day. Every forecast here uses only information that was available before then, and covers all 24 hours, in euro per megawatt hour.

Spain trades inside the Iberian market alongside Portugal, and the two are coupled: most of the time they clear at the same price, and they separate when the interconnection between them is full and cannot carry any more power. Each remains its own bidding zone with its own price, and what is forecast here is the Spanish one.

Spain is also a useful place to forecast a price, because it has a great deal of both wind and solar. When the sun is high and the wind is blowing, a large volume of generation with almost no fuel cost arrives at once, and the price can fall a long way within a few hours and climb back the same evening. A day-ahead price in this zone is not a flat line with a morning and evening bump.

The auction clears once and the price it sets is final, which is what makes the record on this page possible. Each published forecast is written once and never changed, and the price the auction actually cleared at is placed beside it hour by hour as soon as it settles, including on the days the forecast was wrong. Hours are the CET auction day, which is also Spanish local time.

The price forecast and the Spanish wind forecast are separate products, scored separately, and each has its own record on this page.

Forecasting wind in Spain

Spain operates one of the largest onshore wind fleets in the world, concentrated in Castilla y León, Galicia and Aragón. The forecast covers Spanish onshore wind and is scored against the day-ahead forecast Red Eléctrica publishes through the ENTSO-E Transparency Platform.

The Spanish fleet is concentrated in Castilla y León, Galicia, Aragón and Andalusia, and a great deal of it sits on ridges and elevated ground rather than open plain. Terrain of that kind is the classic difficulty in wind forecasting. A weather model works on a grid several kilometres wide and reports an average wind for each cell, while a turbine on a ridge crest inside that cell experiences something quite different, because the ridge accelerates the flow in a way the grid cannot represent. The effect is a limit shared by everyone forecasting the zone.

The benchmark

The benchmark is Red Eléctrica de España's own day-ahead wind forecast for the Spanish bidding zone, published through the ENTSO-E Transparency Platform and captured on the day it appears. Metered generation and installed capacity come from the same source, so the forecast, the benchmark and the outcome all sit on one consistent basis.

What is published for Spain

One value per day: onshore wind output at 11:00 local time tomorrow, as a load factor and in megawatts. Once REE's own forecast for that day is published it is captured and held fixed, and once the metered output is settled both forecasts are scored against it. Every day is added to the record above and nothing is removed or rewritten later. How this is measured.